Microfiltration is process in which contaminants are removed from a fluid (either solid, liquid or gas) by passage through a macroporous membrane. For example, typical microfiltration membrane pore sizes may range from about 0.1 to 10 micrometers. Membrane filters are used in a variety of applications, such as water filtration, biomedical, and biotechnology applications, for example.
One example microfiltration device is disclosed in U.S. Pat. No. 5,919,364 to Lebouitz et al. This patent discloses microfabricated filters constructed with permeable polysilicon membranes. The filters include a frame structure having a plurality of openings therethrough and a permeable polysilicon membrane disposed over the openings in the frame structure. The frame structure provides support for the permeable polysilicon membrane.
Another filtration approach is set forth in U.S. Pat. Pub. No. 2003/0042176 to Alderson et al. This publication discloses a method of separating at least part of one or more components from a mixture of components includes exposing the mixture to a porous barrier. The barrier is formed of a material structure having, or behaving in the manner associated with, a negative Poisson ratio.
Despite the existence of such configurations, further enhancements may be desirable for microfluidic filtration and/or fluid mixing applications.